The instant preferred embodiment relates to a differential cage for a differential gear.
JP-A 62-132 055 discloses a differential cage member of cup shape formed at the bottom of the cup with a bearing projection to support an axle driving shaft. The open other end of the cup is surrounded by an axle drive gear forged together with the cup, and is closed by a cover which comprises a bearing projection aligned with the aforementioned bearing projection to support the other axle driving shaft and is screwed to the axle drive gear by way of a radial flange. Work on the interior of the cup can be performed from the open end thereof. The compensating gears and axle driving gears of the differential gear are introduced into the differential cage member through the open end of the cup and are mounted together with a pin on which the compensating gears are supported, whereupon the cover is fastened to the axle drive gear.
JP 09-233 784 discloses a differential cage comprising an axle driving gear which is forged in one piece with the differential cage member, the latter having axial bores of such size that the compensating gears and driving gears can be introduced into and mounted in the hollow interior thereof through one of the axial bores. Bearing sleeves are inserted in the axial bores, one bearing sleeve being press fitted at one end of the differential cage member and another different bearing sleeve being positioned and fixed at the opposite end by means of bendable clamping fingers.
Both known differential cages involve considerable installation expenditure. With the Japanese '055 patent the bores in the radial flange must be presented so precisely that the bearing projection of the cover determines a precise radial support for the axle-driving shaft to be introduced into the bearing projection. Furthermore, when screwing the cover to the flange, it must always be assured that the threading force will not strain or distort the cover so that, upon due alignment for installation, the bearing projection thereof will not become displaced from its radial and axial position for supporting the axle driving shaft. Moreover, precise finishing is required of the mounting surfaces of the flange and of the differential cage member to guarantee precise axial positioning support of the axle-driving shaft.
When press fitting the bearing sleeve in the differential cage according to the Japanese '784 patent the bearing projection of the bearing sleeve needs to be reworked to offer precise support for the axle driving shaft because torsional tensions and extension caused by the press fitting or shrinking procedures must be compensated. When using clamping fingers for attachment a great many installation steps are needed which is why this kind of attachment of the bearing sleeve is expensive and also because of the configuration of the clamping fingers on the bearing sleeve or the differential cage member. In addition, in the case of clamping, precise axial positioning can be obtained reliably only by readjusting or reworking the bearing projection.